1. Field of the Invention
This invention generally relates to an internal transmission hub assembly. More specifically, the present invention relates to an internal transmission hub assembly that includes an internal positioning member.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle internal transmission hub assembly.
The internal transmission hub assembly is typically a rear wheel hub that includes an internal gearing mechanism that can be shifted to provide a plurality of power transmission paths (gear ratios) for a cyclist.
With such an internal transmission hub assembly, a cyclist changes pedaling speeds by manipulating a conventional lever actuating shifting mechanism installed on or adjacent to the handlebars of the bicycle. Movement of the lever actuating shifting mechanism is transmitted to the internal transmission hub assembly by a Bowden-type cable that is operably connected to a shift mechanism within the internal transmission hub assembly. Changes in the position of the lever actuating shifting mechanism cause corresponding changes in the selection of a power transmission path (gear ratio).
A problem with such an internal transmission hub assembly and conventional lever actuating shifting mechanism is that positioning of the elements within the internal transmission hub assembly is accomplished solely by the positioning of the lever actuating shifting mechanism and the cable. If the lever actuating shifting mechanism is not set to exactly the correct position or orientation, the appropriate elements within in the internal transmission hub assembly may not properly align. Such an improper alignment of elements within the internal transmission hub assembly requires minute movements of the conventional lever actuating shifting mechanism in order for the desired selection of power transmission paths.
Internal transmission hub assemblies typically include a pawl control member that is shaped and dimensioned to move along an arcuate path around a hub axle. The pawl control member includes at least one control arm with pawl contacting recesses that engage and disengage one-way clutch pawls, thereby providing a means to select a desired power transmission path. Recently, a positioning mechanism has been developed that includes a ring with a plurality of gear teeth that contacts a protrusion at an axial end of the pawl control member. Internal transmission hub assemblies are typically compact mechanisms. A problem with the above described positioning mechanism is that the overall volume of the internal transmission hub assembly must be increased slightly to accommodate the positioning mechanism.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved internal transmission hub assembly that includes a more consistent means for establishing correct and complete shifting of the internal transmission hub assembly in the selection of the desired power transmission paths. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.